Method for preparation of an aqueous glyphosate concentrate

Abstract

A method for preparing an aqueous mixture of glyphosate salts to improve the handling of the mixture, the method comprising forming a homogeneous mixture of at least two bases comprising at least one alkali metal hydroxide, and at least one further base selected from alkali metal hydroxides and nitrogen bases and reacting the mixture of the at least two bases with glyphosate acid in an aqueous reaction medium to provide an aqueous mixture of glyphosate salts wherein the concentration of glyphosate (based on glyphosate acid equivalent) is at least 200 gae/L.

The invention claimed is: 
     
       1. A method for preparing an aqueous mixture of glyphosate salts to improve the handling of the mixture, the method comprising:
 forming a homogeneous mixture of at least two bases comprising at least one alkali metal hydroxide, and at least one further base selected from the group consisting of alkali metal hydroxides and nitrogen bases and 
 reacting the homogeneous mixture with glyphosate acid in an aqueous reaction medium to provide an aqueous mixture of glyphosate salts wherein the concentration of glyphosate (based on glyphosate acid equivalent) is at least 500 gae/L, and wherein the nitrogen base includes at least one nitrogen base selected from the group consisting of ammonia, C 1  to C 10  alkylamine, di-(C 1  to C 6  alkyl)amine and tri-(C 1  to C 6  alkyl)amine and wherein when the homogeneous mixture includes potassium hydroxide and either ammonia or isopropylamine then at least one further base is present selected from the group consisting of said alkali metal hydroxide, ammonia, C 1  to C 10  alkylamine, di-(C 1  to C 6  alkyl)amine and tri-(C 1  to C 6  alkyl)amine, and wherein the aqueous mixture has a mole ratio of total of alkali metal hydroxide and nitrogen bases to glyphosate acid that is in the range of from 0.9:1 to 1.3:1. 
 
     
     
       2. The method according to  claim 1  wherein the at least one alkali metal hydroxide is selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide. 
     
     
       3. The method according to  claim 1  wherein the homogeneous mixtures of at least two bases comprises at least two alkali metal hydroxides selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide. 
     
     
       4. The method according to  claim 1  wherein the concentrate of glyphosate salts is at least 550 gae/L. 
     
     
       5. The method according to  claim 1  wherein the concentration of the glyphosate is at least 600 gae/L. 
     
     
       6. The method according to  claim 1  wherein the concentration of glyphosate is at least 610 gae/L. 
     
     
       7. The method according to  claim 1  wherein the concentration of glyphosate is at least 620 gae/L. 
     
     
       8. The method according to  claim 1  wherein the nitrogen bases comprise at least one of methylamine, dimethylamine, isopropylamine, diisopropylamine and triethylamine. 
     
     
       9. The method according to  claim 1  wherein the homogeneous mixture of at least two bases includes at least one selected from the group consisting of sodium hydroxide, methylamine, dimethylamine and triethylamine. 
     
     
       10. The method according to  claim 1  comprising loading the aqueous mixture of glyphosate salts into containers of volume in the range of 0.1 to 10,000 liters to substantially fill the containers, transporting the filled containers and dispensing the aqueous mixture of glyphosate salts from the containers. 
     
     
       11. The method according to  claim 10  wherein the aqueous mixture of glyphosate salts is pumped into the containers. 
     
     
       12. The method according to  claim 1  wherein the reaction between the glyphosate acid and bases is carried out at a temperature in the range of from 5° C. to 80° C. 
     
     
       13. The method according to  claim 1  wherein the method further comprises forming a mixture of at least one further acid herbicide with glyphosate acid and reacting the homogeneous mixture of the at least two bases with the mixture of glyphosate acid and at least one other acid herbicide to provide a composition comprising a mixture of glyphosate salts and a mixture of the at least one further acid herbicide salt, wherein the composition has a concentration of glyphosate salts that is at least 500 gae/L and a molar ratio of total of alkali metal hydroxide and nitrogen bases to total acid herbicides in the range of from 0.9:1 to 1.3:1. 
     
     
       14. The method according to  claim 13  wherein the at least one acid herbicide is selected from the group consisting of dicamba, clopyralid, 2,4-D, MCPA and mecoprop. 
     
     
       15. The method according to  claim 13  wherein the glyphosate acid comprises at least 80% by weight of the total acid herbicide including glyphosate acid. 
     
     
       16. The method according to  claim 1  further comprising addition of a surfactant wherein the concentration of the surfactant is in the range of from 0.1 to 20% by weight of the aqueous glyphosate concentrate composition. 
     
     
       17. The method according to  claim 16  wherein the surfactant comprises one or more selected from the group consisting of quaternary ammonium surfactant; etheramine surfactants; alkylether and amine surfactant combinations; acetylenic diol and alkyl(poly)glycoside surfactant combinations; lipophilic fatty amine ethoxylate surfactants; alkoxylated amine surfactants; betaine surfactants; alkyl polyglycoside agents; secondary or tertiary alcohol surfactants; silicone copolymer wetting agents and trialkylamine oxide or quaternary amine or trialkylbetaine surfactant combinations; sorbitan fatty acid ester and amine, quaternary ammonium or alkylglycoside surfactant combinations; surfactants derived from alkanethiols; polyoxyalkylene trisiloxane surfactants; super-wetting agents comprising silicone-based and fluorocarbon-based surfactants; supra-molecular aggregates comprising one or more amphiphilic salts having a glyphosate anion and cation derived by protonation of secondary or tertiary oily amines; alkoxylated primary alcohol surfactants; alkyl polysaccharide derivates; alkyl polyglycoside and ethoxylated alcohol combinations; alkylglucosides; surfactants comprising polyhydroxyhydrocarbyl and amine functionality; alkylglycoside and alkoxylated alkylamine surfactant combinations; alkyldiamine tetraalkoxylate surfactants; succinic acid derivatives; alkoxylated amido amines; sugar glycerides; diamine surfactants; widely-bridged alcohol polyethoxylates; water-soluble long-chain hydrocarbyl dimethylamine oxides and quaternary ammonium halide combinations; hydroxyalkylammonium adjuvants; polyether diamine surfactants; cationic, anionic, nonionic or zwitterionic silicone adjuvants; organosilicone surfactants and diphenyl oxide sulfonate surfactant combinations; a range of ether phosphate adjuvants; phosphorous surfactant adjuvants; polyglycerol and polyglycerol derivatives; C8-C22 sarcosinate or sarcosinate salts; ethoxylated vegetable oils; polyethoxylated dialkylamine surfactants; C10-C18 alkylpolyglycol ether sulfates; Sucrose & Sorbital Surfactants; Sorbitan Esters; Ethoxylated Saccahrose Esters; Coco Amido Propyl Dimethylamine Akyldimethylamines; Phosphated Esters Tallow Amine Surfactants; Trisiloxanes; TEA and MDEA Esterquats; Dimethylethanolamine based Esterquats; Saccharides; Alkyl Polypentosides (APP); Polyglycerines; Etheramine Alkoxylates; Sorbitan Monolaurate; Pine Terpinic compounds; Cocoamine ethoxylates; Acrylates & Latex compounds; (Ethoxylated)Oleyl Alcohols; Alkylamine Alkoxylates; Etheramine Alkoxylates/Alkyl Etheramine; Quaternary Ammonium Salts/Ammonium Quaternary Derivatives; Quat Amines; Amine Oxides; Dialkoxylates Amines; Alkyl Alkoxylated Phosphates; Aminated Alkoxylated Alcohols; Dialkoxylated Amines; Carboxylates; Alkylethersulfates; Disodium sulfosuccinates/Succinates; Polyether Amines; Cocoamidopropyl betaines and salts of fatty acids. 
     
     
       18. The method according to  claim 1 , wherein said forming the homogeneous mixture and said reacting the homogeneous mixture with glyphosate acid improves the handling of the resulting aqueous concentrate by reducing the viscosity of the aqueous concentrate as compared to an aqueous concentrate containing the same concentration of glyphosate salt which is formed by either (i) sequential mixing of the at least two bases with glyphosate acid or (ii) mixing preformed glyphosate salts of the at least two bases.